The present invention relates to appliances of the type having a monitor mounted to a chassis and disposed in a housing, such as for example, televisions and computers, including all-in-one computers and computers having separate monitors. An appliance such as a personal computer typically includes a monitor or CRT mounted in a metal chassis that is, in turn, encased within an outer housing formed, for example, of plastic. The operating equipment for the monitor (e.g., power source, mother board, disc drive, etc.) can be carried by a separate chassis; or in the case of an all-in-one type of personal computer, the monitor and associated operating equipment can share a common chassis. A monitor-carrying chassis typically comprises a base portion, and a rectangular frame oriented vertically at the front of the base portion for receiving the screen of the monitor.
The housing may comprise interconnected front and rear sections, the front section being in the form of a rectangular bezel which surrounds (frames) the outer periphery of the monitor screen. The front and rear housing sections are joined together by means of screws which pull adjoining edges of those housing sections together.
The location of the bezel relative to the monitor is important in order to ensure that the bezel properly frames the monitor. That is, if the bezel were spaced forwardly from the monitor screen, an excessive and unsightly gap could be formed between the bezel and screen presenting the risk of foreign objects becoming lodged therein. Thus, the bezel should abut the front of the monitor. Also, the junction or reveal between the bezel and rear housing section should be straight (i.e., non-wavy) and flush.
Additionally, the location of the bezel should be accurate with respect to any control switches mounted on the chassis. In that regard, certain control switches may be mounted to the chassis, with access to those switches afforded through the front housing. For some controls, a pass-through connection is sufficient, e.g., a shaft for a knob, but for one preferred type of actuating mechanism wherein a switch includes an actuator that must be moved along a certain axis, e.g., by being pressed, a movable component such as a button carried by the bezel should just contact or perhaps should not quite contact a corresponding actuator of a switch fixed to the chassis when in a resting position, yet be able to be brought into contact with and press the corresponding actuator with only a small total travel distance of the button. The switch actuators typically have a throw of about 0.5 mm, so the positioning of a button in a housing over a control switch should preferably be accurate to a tolerance of about .+-.1.0 mm.
To reiterate, the front housing (bezel) must conform closely to the surface of the monitor screen and also must meet the rear housing accurately. The rear housing must meet the chassis and the front housing accurately.
However, in the prior art, the fit between chassis and monitor, in particular, the position of the monitor screen relative to the chassis, has not been controlled with sufficient precision, which in turn has meant that tolerances between front and rear housing, chassis and monitor could not be held to small dimensions.
In that regard, it has been conventional to assemble a personal computer by attaching the bezel to the monitor, then mounting the chassis and the rear housing section to the bezel. The mounting of the bezel to the monitor involves the use of screws extending between bosses on the bezel, and flanges on the monitor for drawing the bezel and monitor together. However, the manufacturing accuracy of the flanges relative to the rest of the monitor, e.g., relative to the monitor screen, is about .+-.2.0 mm, which means that as the screws are tightened to draw the bosses and flanges together, any inaccuracies between the flange locations will cause the bezel to become warped, making for an unsightly reveal between the bezel and rear housing section.
Moreover, the manufacturing accuracy of .+-.2.0 mm for the monitor flanges exceeds the above-mentioned tolerance of .+-.1.0 mm required to ensure proper operation of control switches mounted on the chassis. Therefore, difficulties may be encountered in ensuring proper operation of those switches.
Furthermore, after the bezel is mounted to the monitor, that bezel/monitor unit must be further handled as a unit in order to be mounted in the chassis, whereupon the bezel can become scratched or otherwise damaged.
In the above-mentioned concurrently filed application Ser. No. 08/415,469 there are disclosed methods and apparatus for assembling the chassis, monitor, and housing components of a personal computer in a manner which enables the adjoining edges of the front (bezel) and rear housing sections to be joined together in flush engagement (no warping), and which enables push buttons on the bezel to be properly positioned with respect to switches on the chassis. Also, handling and damaging (e.g., scratching) of the bezel is minimized. Those methods and apparatus involve the use of a fixture against which the monitor and chassis are positioned to establish a predetermined positional relationship between the monitor and chassis. Then, the monitor and chassis are interconnected through the use of novel brackets which are screwed to the monitor flanges to fix that predetermined positional relationship. By using the fixture and brackets to establish the positional relationship between the monitor housing, any positional inaccuracies between the flanges of the monitors will not affect the positioning of the monitor relative to the chassis or other housing.
After the computer has been in use, however, it may become necessary for the monitor to be removed from the chassis for repair or replacement. When the repaired monitor or new monitor is then installed into the chassis, the special alignment fixture may not be available, whereupon the original precision positioning of the monitor may be lost, thereby resulting in the aforementioned problems.
It would be desirable, therefore, to enable a repaired or replacement monitor to be installed in a chassis easily, rapidly and with a relatively high degree of precision, without the need for special alignment fixtures.